“PHP suEXEC Max Conn” can be adjusted based how many and how big the sites has been hosted. For a server dedicated for a large Wordpress or vBulletin site, you can safely increase it to “10”, “15” or “20”, try different value and see what is the best for you.

Different system/platform, default Apache Configuration File is different. For example, for CentOS, it is located at /etc/httpd/conf/httpd.conf; for WHM/cPanel, it is /usr/local/apache/conf/httpd.conf.